Spicatin,a protolimonoid from Entandrophragma spicatum

The hexane extract of the timber of Entandrophtagma spicatum is shown to contain a new protolimonoid, spicatin, which has been identified as 24-hydroxygrandifoliolenone. The known entandrophragmin and a new ester closely related to bussein were also obtained.     

A new saponin from seeds of Amoora rohituka

Phytochemical examination of the seeds of Amoora rohituka resulted in the isolation and identification of a new saponin, stigmasta-5,24(28)-dien-3β-O-β-d-glucopyranosyl-O-α-l-rhamnopyranoside.     

Structure and stereochemistry of limonoids of Cabralea eichleriana

From Cabralea eichleriana seeds, the following compounds have been isolated: cabraleone, cabraleadiol, fissinolide, 3-deacetylfissinolide, gedunin, 7-deacetoxy-7-oxygedunin, 7-deacetoxy-7-hyd-roxygedunin, methyl angolensate, and three new compounds, 7-deacetoxy-7-hydroxyphotogedunin, cabralin, and isocabralin. Cabralin has also been obtained by photolysis of fissinolide.     

大叶山楝根的化学成分及细胞毒活性研究

该研究从大叶山楝根95%乙醇提取物的乙酸乙酯萃取物中分离得到10个化合物,经波谱解析分别鉴定为schleicheol 2(1),β-扶桑甾醇(2),fregenedadiol(3),异巴西红厚壳素(4),丁香酯素(5),表丁香酯素(6),graminone A(7),sylvatesmin(8),Z-6-十九烯酸甲酯(9),棕榈酸(10)。其中,化合物1-4、化合物7-9为首次从山楝属植物中分离得到。细胞毒活性测试结果表明,化合物1和化合物2对人胃癌细胞SGC-7901生长具有一定的抑制活性。     

(+)-8-Hydroxycalamenene: A fish-poison principle of Dysoxylum acutangulum and D. Alliaceum

A fish-poison principle of Dysoxylum acutangulum and D. alliaceum has been identified as (+)-8-hydroxycalamenene, a new natural sesquiterpene phenol. This compound shows not only significant toxicity against fish but also antibacterial activity.     

Distribution and structural aspects of extrafloral nectaries in Cedrela fissilis (Meliaceae)

The occurrence of extrafloral nectaries (EFNs) in Meliaceae has been reported for some genera, but little anatomical data are available. Therefore, to determine the distribution and structural aspects of EFNs, Cedrela fissilis Vell. leaves in different stages of development were collected, fixed, and processed for light and scanning electron microscopy. On the petiole, rachis and petiolule, EFNs were found to be arranged predominantly towards the abaxial surface, while their occurrence in leaflet blades was restricted to the abaxial surface of the major veins, noticeably on the midrib. Basal leaflets displayed few EFNs; however, we observed an increase towards the leaf's apex. The leaf can contain more than 300 inconspicuous EFNs, which show secretory activity throughout the leaf's life. Two EFN morphotypes were visible: flattened or elevated, both circular or slightly elliptical and similar in origin and tissue composition. The secretory tissue is embedded in the rachis cortex or in the major veins of the leaf blade and EFNs are not vascularized. The EFN secretory pole shows a uniseriate epidermis with compactly arranged cells and a thin cuticle; stomata and trichomes are absent. The observation of ant visits at these structures reinforces the assumption that EFNs mediate ant–plant interactions and play a protective role against herbivores throughout the life of a leaf.     

酸渣树中一个新的黄烷类化合物

从酸渣树(Carapaguianensis Aubl.)枝条的乙醇提取物中首次分离到7个化合物,通过波谱方法鉴定,它们分别是:()-epicatechin-3-O-(3",5"-di-O-methyl)gallate(1)、(-)-catechin(2)、sciadopitysin(3)、cl eomi scosin B(4)、photogedunin(5)、chi socheton compound F(6)和odoratone(7).其中,化合物1为新黄烷类化合物,2～7为首次从该植物中分离得到.补充了化合物5的13C-NMR谱数据.活性测定显示,化合物7对大菜粉蝶(Pieris brassicae)三龄幼虫具有较强的杀虫活性,化合物2有一定的活性,而正丁醇部分只有很弱的活性.     

Ekebergin,a limonoid extractive from Ekebergia capensis

Seeds of Ekebergia capensis contain a crystalline limonoid to which the name ekebergin has been given. This has been identified as a diacylated methyl angolensate derivative.     

Phytotoxicity of alkaloids,coumarins and flavonoids isolated from 11 species belonging to the Rutaceae and Meliaceae families

Meliaceae and Rutaceae families are known for the high diversity of their secondary metabolites, which include many groups that represent a rich source of structural diversity, and are good candidates as sources of allelochemicals that could be useful in agriculture. In the work described here the bioactivity profiles were evaluated for 3 alkaloids (1–3), 12 coumarins (4–15), 2 phenylpropanoic acid derivatives (16 and 17) and 14 flavonoids (18–31) from 11 species belonging to the Meliaceae and Rutaceae families. All compounds were tested in the wheat coleoptile bioassay and those that showed the highest activities were tested on the STS (Standard Target Species) Lepidium sativum (cress), Lactuca sativa (lettuce), Lycopersicon esculentum (tomato), and Allium cepa (onion).Most of the isolated compounds showed phytotoxic activity and graveoline (3), psoralen (8), and flavone (18) were the most active, with bioactivity levels similar to that of the commercial herbicide Logran^®. The results indicate that these compounds could be involved as semiochemicals in the allelopathic interactions of these plant species.